Modeling and fabrication of hollowed scaffolds with interconnected variational porosity architecture

This paper presents a novel computer-aided modeling of 3D hollowed tissue scaffolds with a controlled internal architecture. Functionally gradient variational porosity architecture is proposed with continuous material deposition planning scheme. The complex internal architecture of scaffolds is discritized into sub-regions accumulated from ruling lines that are generated from outer to inner features. The desired pore size and hence the porosity have been achieved by geometrically partitioning those sub-regions based on the area while meeting the tissue scaffold design constraint. Thus the desired controlled variational porosity along the scaffold architecture has been achieved with the combination of two geometrically oriented consecutive layers. A continuous, interconnected and optimized tool-path has been generated for both layers aiming at the standard solid free form fabrication process. A zigzag pattern tool-path has been proposed for accumulated sub-region layer. And a concentric spiral like optimal tool-path pattern has been derived for the successive layer to ensure fabricatable continuity along the structure. A micro-nozzle biomaterial deposition system driven by NC motion control has been used to fabricate sample designed structure with desired pore size and porosity level. Besides proper characterization of the fabrication sample has been performed to validate the proposed methodology. Moreover a comparative study between proposed design and conventional cartesian coordinate scaffolds has been performed. The results demonstrate significant reduction in design error with the proposed method.